On page 32 (chapter 3):
"PUT requests tend to look a lot like POSTs: you parse the input, modify the data store, and return. In fact, parsing the input is usually identical between PUT and PUT routes for a given type."

"What can you do instead? You can write a custom serializer. A custom serializer basically represents two partial functions: one function accepts a JValue and returns a NutritionFacts; the other function knows how to create a NutritionFacts from a JSON document."

Should be:

"What can you do instead? You can write a custom serializer. A custom serializer basically represents two partial functions: one function accepts a JValue and returns a NutritionFacts; the other function knows how to create a JSON document from a NutritionFacts."

In the Kindle (.mobi) version, I have some weird characters in chapter "8.1.4. Running your tests":

"You have your first test and, not unexpected1y, your first test fai1ure. Cheer up: this is a good thing! It's good practice to write the test, see it fai1, and then imp1ement (or fix) the main code. Seeing the test switch from fai1ing to passing with a change to the main code serves as a sort of test of the tests, warding off fa1se positives."

Many "L" characters seems to have been replaced with the number "1".

I don't see this problem in the PDF version. I don't know if it's some kind of OCR failure or some ebook tracking scheme, but it's really annoying.